DESCRIPTION (from the application): The Micro array Core of the Program Project (Core C) will: 1) provide training and consultation in the methodologies, necessary for the use of micro arrayed cDNAs, (this includes discussion of experimental design, isolation of RNA generation of dye-labeled cDNAs, development of standard RNA reference pools; and hybridization of chips with labeled cDNA pools); 2) carry out the labeling and hybridization for program project members; 3) provide chips and reagents necessary for labeling cDNA probe populations at reduced cost; and 4) scan the hybridized slides and provide the program project members with the processed quantitative data derived from the micro array. The Micro array Core provides the capability to conduct a broad screen of gene expression changes (e.g., old versus young) that is far more efficient than current technologies.